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Merge pull request #2868 from takluyver/import-performance...
Merge pull request #2868 from takluyver/import-performance Import performance Defer various imports for a small reduction in startup time. IPython.lib.__init__ previously loaded IPython.lib.inputhook to export some of its functions. This meant that importing anything from IPython.lib also loaded inputhook. For now, I've just removed that import, but that is an API change, because the functions are no longer accessible as e.g. IPython.lib.enable_qt4 Added a note about the API change. Timing command, borrowed from Openoffice to simulate cold start: $ sync ; echo 3 | sudo tee /proc/sys/vm/drop_caches; time ipython3 -c pass Results with this branch: 7.68, 7.64, 7.35, 7.38 s 'real' Results with master: 8.17, 8.04, 7.81, 7.77

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envpersist.py
92 lines | 2.4 KiB | text/x-python | PythonLexer
# -*- coding: utf-8 -*-
""" %env magic command for storing environment variables persistently
"""
from IPython.core import ipapi
from IPython.core.error import TryNext
ip = ipapi.get()
import os,sys
def restore_env(self):
ip = self.getapi()
env = ip.db.get('stored_env', {'set' : {}, 'add' : [], 'pre' : []})
for k,v in env['set'].items():
os.environ[k] = v
for k,v in env['add']:
os.environ[k] = os.environ.get(k,"") + v
for k,v in env['pre']:
os.environ[k] = v + os.environ.get(k,"")
raise TryNext
ip.set_hook('late_startup_hook', restore_env)
def persist_env(self, parameter_s=''):
""" Store environment variables persistently
IPython remembers the values across sessions, which is handy to avoid
editing startup files.
%env - Show all environment variables
%env VISUAL=jed - set VISUAL to jed
%env PATH+=;/foo - append ;foo to PATH
%env PATH+=;/bar - also append ;bar to PATH
%env PATH-=/wbin; - prepend /wbin; to PATH
%env -d VISUAL - forget VISUAL persistent val
%env -p - print all persistent env modifications
"""
if not parameter_s.strip():
return os.environ.data
ip = self.getapi()
db = ip.db
env = ip.db.get('stored_env', {'set' : {}, 'add' : [], 'pre' : []})
if parameter_s.startswith('-p'):
return env
elif parameter_s.startswith('-d'):
parts = (parameter_s.split()[1], '<del>')
else:
parts = parameter_s.strip().split('=')
if len(parts) == 2:
k,v = [p.strip() for p in parts]
if v == '<del>':
if k in env['set']:
del env['set'][k]
env['add'] = [el for el in env['add'] if el[0] != k]
env['pre'] = [el for el in env['pre'] if el[0] != k]
print "Forgot '%s' (for next session)" % k
elif k.endswith('+'):
k = k[:-1]
env['add'].append((k,v))
os.environ[k] += v
print k,"after append =",os.environ[k]
elif k.endswith('-'):
k = k[:-1]
env['pre'].append((k,v))
os.environ[k] = v + os.environ.get(k,"")
print k,"after prepend =",os.environ[k]
else:
env['set'][k] = v
print "Setting",k,"to",v
os.environ[k] = v
db['stored_env'] = env
def env_completer(self,event):
""" Custom completer that lists all env vars """
return os.environ.keys()
ip.define_magic('env', persist_env)
ip.set_hook('complete_command',env_completer, str_key = '%env')